Crab chitin

A number of studies have examined the antioxidant activities of chitosan from various sources. Park et al. (2004a) prepared three kinds of partially deacetylated hetero-chitosans such as 90% deacetylated, 75% deacetylated, and 50% deacetylated chitosan from crab chitin, and their antioxidant properties were measured using electron spin resonance spectrometry. Park and coworkers found that their antioxidant activities were dependent on the DD, and the 90% deacetylated chitosan showed the highest free radical scavenging activities. Yen et al. (2008) also found that a sample with more amino groups at the C-2 position showed the highest antioxidant activity. Tomida et al. (2009) examined the protective effects of seven different MW chitosans on plasma protein from oxidation by peroxyl radicals. In the ability to protect plasma protein from... 

The Raman specfra of spindles are almosf identical wifh fhe spectrum of crab chitin. The close resemblance of the spectral profile between 1000... 

FIGURE 2.17 The Raman spectra of (a) the reference crab chitin and (b) the spindles of Cratena peregrina. 

Crab chitin, and chitin from the diatom Thalassiorira fluviatilis dissolves in hexafluoro-2-propanol far-u.v. and c.d. spectra of solutions, gels, and films of the chitin have been recorded. A trans-amide conformation and intermolecu-lar hydrogen bonding are proposed as the important determinants of the observed solid state c.d. spectra. 

Chitin and Chitan. Marchessault et al. (1960) have examined the tilting infrared spectra of two chitin samples crab chitin crystallites and larval cuticle chitin of the blowfly. The general principles for interpreting and the practical procedures for obtaining tilted spectra of polymers have been discussed by Liang and Marchessault (1960) and by Pearson et al. (1960). Figure 6.10 presents schematically the tilting... 

Fig. 6.11. Tilting spectra for crab chitin crystallites (A) and blowfly larval chitin (B) with electric vector...

A CHT specimen (company Chimme , Russia) obtained by alkaline deacetylation of crab chitin was chosen as the object of investigation. To prepare CHT film specimens semi-diluted (2g/dl) solutions were made by dissolving a dry polymer weight at room temperature for 8-10 hr. Acetic acid with the concentration of 170 g/dl was used as the solvent. 

Takeda, M. and H. Katsuura. 1964. Purification of king crab chitin. Suisan Daigaku Kenkyu Hokoku. 13 109. 

Chitin, a polysaccharide-based material, is present in the shells of such sea creatures as shrimps and crabs. Chitin is biodegradable by nature, and when acetyl groups i.e. CH3-CO, are removed from the chitin molecules, chitosan is produced with exposed amine groups. The antimicrobial capabilities of chitin/chitosan are based on its cationic nature, which is capable of binding with anionic pathogens and making them ineffective (Aranaz et a/.,2009,p203). 

The object of investigation was a chitosan (ChT) specimen produced by the company Bio progress (Russia) and obtained by acetic deacetylation of crab chitin (degree of deacetylation -84%) with M =334000. As the medicinal substance (MS) used an antibiotic amikacin (AM) quadribasic aminoglycoside, used in the form of salts sulfate (AMS) and chloride (AMCh). Chemical formulas of objects of research and their symbols used in the text are given in Table 13.1. 

LDPE 10803-020 (90,000 molecular weight, 53% crystallinity degree, and 0,917 g/sM density) and chitosan samples of Bioprogress Ltd. (Russia) obtained by alkalinedeacetylation of crab chitin (deacetylation degree 84%), and M = 115000 were used as components for producing biodegradable polymer films. 

The object of investigation was a CHT specimen produced by the company Bioprogress (Russia) and obtained by acetic deacetylation of crab chitin with a molecular weight of M =l 13000. As the enzyme preparation was used hyaluronidase enzyme preparation ( Liraze ) production of Microgen (Moscow, Russia). The concentration of the enzyme preparation was 0.1,0.2 and 0.3 g/L. Acetic acid of 1 g/ concentration was used as a solvent. CHT concentration in solution ranged from 0.1 to 5 g/dL. 

All benthic organisms and sediment were obtained from the waters of central Chesapeake Bay or the Patuxent River subestuary (9-15% salinity). Samples were either processed immediately or kept on ice until processing. Sediment used for the enzyme induction study was brought into the lab and mixed thoroughly. Some of this mud served as control and replicate samples contained additions of blue crab chitin presented as 2.5-4 mm particles. One liter polyethylene tubs were filled to the brim with experimental or control mud and placed under ambient flowing seawater. 

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